1. Field of the Invention
This invention relates to and has among its objects the continuous mechanical wrapping of objects, particularly those having a poorly defined shape or which are non-uniform in size or shape.
2. Description of the Prior Art
A mechanical wrapper for wrapping an object in heat-sealable film is disclosed by Reid et al. (U.S. Pat. No. 3,466,844). In this apparatus a center-folded web of flexible heat-sealable film is intermittently fed forward in package length intervals, with a dwell between successive feed cycles. The film which has the center fold at the bottom is fed through a packaging station where an object is inserted and to a sealing station where means are provided for sealing the opposed walls of the material to enclose the object. The film is conveyed by side-conveyors which engage the outside walls of the film and a horizontal conveyor which supports the film and object.
Saraiski et al (U.S. Pat. No. 3,420,034) discloses a wrapping machine wherein an article is placed in supported, center-folded heat-sealable film, the film is drawn tightly against the article and sealed. Hansen et al (U.S. Pat. Nos. 3,466,840 and 3,505,780) disclose a wrapping machine for wrapping articles such as food stuffs in heat sealable film, wherein the article is placed on a shallow tray and then film is folded about the article and heat sealed. U.S. Pat. No. 4,179,867 granted to Bodalay shows a packaging machine for fabricating individual bag-like containers from a continuous web of film. This device includes web carrier means comprising belts having fingers to supportingly engage the film and convey it to filling and sealing stations.
Characteristic problems of the aforementioned wrapping machines are that they wrap objects of a particular size and shape and thus are poorly adapted for wrapping poorly defined or odd-shaped objects such as lettuce, cauliflower and cabbage or series of foodstuffs such as bunches of carrots or turnips unless the object or series of objects is placed in a tray. Furthermore, the conveyance of the wrapping material is intermittent, being halted during the sealing process, thereby resulting in loss of efficiency of operation.